The Outpatient Research Center for Sensorineural Deafness (ORCSND) has as its objective the study of sensorineural hearing impairments of peripheral and central nervous system origin. The intent of such study is clarification of the manifestations of sensorineural deficits which are misunderstood or unknown. The underlying premise is that each distinctive lesion within the sensorineural auditory complex produces unique effects on hearing functions. To accomplish its ends, the Center supports three major activities: 1) a clinical research facility, the Special Test Unit (STU), which concentrates on detailed evaluation of unusual and/or useful cases of sesorineural damage including disorders of the central nervous system; 2) studies of specific populations of subjects with diagnosed hearing loss or similar arrays of symptoms; 3) study and/or development of procedures and tests to be used in the STU or the population studies.